CN115521781B - A carbon quantum dot with high fluorescence performance for detecting oxytocin and its preparation method - Google Patents

Abstract

The invention discloses a carbon quantum dot with high fluorescence performance for detecting oxytocin and its preparation method and application. The preparation method comprises the following steps: uniformly mixing a carbon source, a nitrogen source and deionized water, and then performing a hydrothermal reaction , to prepare a reaction solution; after cooling, successively filter, dialyze and freeze-dry to prepare carbon quantum dots with high fluorescence performance for detecting oxytocin. The invention obtains nitrogen-doped yellow-green fluorescent carbon quantum dots through hydrothermal reaction, which has good fluorescence performance and excellent water solubility, and is used for the determination of oxytocin, and has the advantages of simple and fast operation, low detection limit and high accuracy. high advantage. The invention relates to the technical field of drug content detection, and solves the problems of complicated operation and low accuracy of the method for detecting oxytocin content in the prior art.

Description

A carbon quantum dot with high fluorescence performance for detecting oxytocin and its preparation method

technical field

The invention relates to the technical field of drug content detection, in particular to a carbon quantum dot with high fluorescence performance for detecting oxytocin and a preparation method thereof.

Background technique

Oxytocin is a neuropeptide composed of 9 amino acids (Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly-HN2), which can promote childbirth and milk secretion. It is extracted from the pituitary gland of pigs and cattle. It can also be prepared by total synthesis, and it is clinically used for uterine bleeding caused by uterine atony or poor contraction after labor induction, oxytocin, postpartum and abortion. At present, the determination methods of oxytocin mainly include biological activity assay, HPLC method, LC/MS method and immunoassay method; among them, the biological activity assay method is complicated to operate, and the determination results are easily affected by individual animal differences and human error; HPLC and LC/MS require instrument support, and are time-consuming and costly; immunoassays are fast and sensitive, but the accuracy is not high. Therefore, there is an urgent need to establish a rapid, sensitive and accurate analytical method for the concentration of oxytocin in oxytocin raw materials, preparations or clinically used drugs.

Contents of the invention

In order to solve the above technical problems, the object of the present invention is to provide a carbon quantum dot with high fluorescence performance for oxytocin detection and its preparation method and application, so as to solve the complicated and accurate operation of the method for detecting oxytocin content in the prior art low-level problem.

The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a method for preparing carbon quantum dots with high fluorescence performance for oxytocin detection is provided, comprising the following steps:

(1) Mix carbon source, nitrogen source and deionized water evenly, then carry out hydrothermal reaction, make reaction solution;

(2) After the reaction solution prepared in step (1) is cooled, it is successively filtered, dialyzed and freeze-dried to prepare carbon quantum dots with high fluorescence performance for detecting oxytocin.

The beneficial effects of the present invention are: the present invention obtains nitrogen-doped yellow-green fluorescent carbon quantum dots through hydrothermal reaction, which has good fluorescence performance and excellent water solubility, and is used for the determination of oxytocin, and has the advantages of simple and fast operation , low detection limit and high accuracy.

On the basis of above-mentioned technical scheme, the present invention can also be improved as follows:

Further, in step (1), the molar volume ratio of carbon source, nitrogen source and deionized water is 0.5mmol:0.25-2mmol:10-25mL.

Further, in step (1), the carbon source is quercetin.

Further, in step (1), the nitrogen source is o-phenylenediamine.

Further, in step (1), hydrothermal reaction is carried out at 160-240° C. for 4-8 hours.

Further, in step (2), the reaction solution is filtered through a membrane with a pore size of 0.2-0.24 μm.

Further, in step (2), the reaction solution is filtered through a membrane with a pore size of 0.22 μm.

Further, in step (2), dialyze for 12-48 hours under the condition of a molecular weight cut-off of 1000-5000 Da.

The present invention also provides carbon quantum dots prepared by the method for preparing carbon quantum dots with high fluorescence performance for detecting oxytocin.

The present invention also provides the application of the above-mentioned carbon quantum dot with high fluorescence performance for detecting oxytocin in the detection of oxytocin content.

A detection method for oxytocin content, comprising the following steps:

(1) The above-mentioned carbon quantum dots with high fluorescence performance for oxytocin detection are mixed with water to prepare a carbon quantum dot solution;

(2) in the carbon quantum dot solution that step (1) makes, add the oxytocin standard solution of different concentrations respectively, take 460nm as the excitation wavelength, measure the fluorescence emission of the carbon quantum dot solution before and after adding the standard solution respectively Spectrum, after the standard solution is added, the carbon quantum dot solution is obtained relative to the fluorescence intensity change value of the carbon quantum dot solution at the maximum emission wavelength before the standard solution is added;

(3) According to the change value of the fluorescent intensity obtained in step (2) and the concentration of the corresponding oxytocin standard solution, draw a standard curve to obtain a linear equation;

(4) In the carbon quantum dot solution prepared in step (1), add the oxytocin solution to be detected, and use 460nm as the excitation wavelength to measure the fluorescence of the carbon quantum dot solution before and after adding the oxytocin solution to be detected respectively Emission spectrum, obtain the change value of the fluorescence intensity of the carbon quantum dot solution at the maximum emission wavelength of the carbon quantum dot solution after the oxytocin solution to be detected is added relative to the carbon quantum dot solution before the oxytocin solution to be detected is added, and substitute into the linear equation to obtain the oxytocin solution to be detected concentration of the solution.

Further, in step (1), the concentration of the carbon quantum dot solution is 0.05-1.5 mg/mL.

Further, in step (1), the concentration of the carbon quantum dot solution is 0.5 mg/mL.

Further, in step (2), the volume ratio of the carbon quantum dot solution to the oxytocin standard solution is 1:0.5-2.

Further, in step (2), the volume ratio of the carbon quantum dot solution to the oxytocin standard solution is 1:1.

Further, in step (2), the concentrations of different oxytocin standard solutions are 0.2IU/mL, 0.36IU/mL, 0.4IU/mL, 0.6IU/mL, 0.8IU/mL, 1.2IU/mL, 1.6IU /mL, 2IU/mL, 3IU/mL, 4IU/mL, 5IU/mL, 6IU/mL, 7IU/mL, 8IU/mL, 9IU/mL, and 10IU/mL.

Further, in step (3), the concentration of oxytocin standard solution is in the range of 0.2-5IU/mL, the linear equation is y=29298x+17654, R ² =0.9957, wherein, y is the change value of fluorescence intensity, x is Concentration of oxytocin standard solution, R is a linear fitting constant.

Further, in step (3), the linear equation for the concentration of oxytocin standard solution in the range of 5-10IU/mL is y=6894x+127986, R ² =0.9928, wherein, y is the change value of fluorescence intensity, x is the contraction value Concentration of uterine standard solution, R is a linear fitting constant.

Further, in step (4), the detection limit of oxytocin is 0.0196IU/mL.

Further, the detection limit LOD is calculated by the following method: the fluorescence intensity of the carbon quantum dot solution before the standard solution is added in the step (2) is repeatedly measured 11 times, the standard deviation of the blank fluorescence intensity is calculated, and the standard curve is obtained according to the standard curve of the step (3) Slope, with signal-to-noise ratio S/N=3, use the following formula to calculate the detection limit LOD:

LOD=3×Standard deviation of blank fluorescence intensity/Slope of standard curve

The present invention has the following beneficial effects:

1. The carbon source used in the present invention is quercetin, which is rich in quercetin in many plants, and is rich in resources, cheap and easy to obtain; the present invention uses water as the reaction solvent, and is synthesized by a one-step hydrothermal method, and the operation process is simple and environmentally friendly. , economical and efficient, has very important social significance.

2. Compared with traditional sensing probes based on organic dyes, carbon quantum dots have superior characteristics as fluorophores. They do not have photobleaching and toxicity problems, and the presence of functional groups such as hydroxyl, carboxyl, carbonyl, and epoxy groups on the surface , endow carbon quantum dots with solubility in water, meanwhile, these groups pave the way for surface functionalization of quantum dots and provide selectivity for target analytes.

3. The present invention uses simple and easy-to-obtain quercetin as a raw material doped with polyamino small molecules to prepare carbon quantum dots with high fluorescence performance, and successfully uses it for the determination of oxytocin content. The assay method of the present invention has The method has the advantages of convenient construction, high sensitivity, good specificity and convenient use, and can be applied to the determination of oxytocin raw materials and preparations thereof, as well as the concentration of oxytocin in clinically used drugs.

Description of drawings

Fig. 1 is the high-resolution transmission electron microscope figure of the carbon quantum dot that embodiment 1 makes;

Fig. 2 is the particle size distribution figure of the carbon quantum dots that embodiment 1 makes;

Fig. 3 is the infrared spectrogram of the carbon quantum dot that embodiment 1 makes;

Fig. 4 is the ultraviolet spectrogram of the carbon quantum dot that embodiment 1 makes;

Fig. 5 is the fluorescence spectrogram of the carbon quantum dot that embodiment 1 makes;

Fig. 6 is the photostability test figure of the carbon quantum dot that embodiment 1 makes;

Fig. 7 is the linear relationship diagram (0.2-5IU/mL) of the fluorescence intensity of the carbon quantum dots prepared in Example 1 and the concentration of oxytocin;

Fig. 8 is a graph showing the linear relationship between the fluorescence intensity of the carbon quantum dots prepared in Example 1 and the concentration of oxytocin (5-10 IU/mL).

Detailed ways

The principles and features of the present invention are described below in conjunction with the accompanying drawings, and the examples given are only used to explain the present invention, and are not intended to limit the scope of the present invention. Those who do not indicate the specific conditions in the examples are carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used were not indicated by the manufacturer, and they were all conventional products that could be purchased from the market.

Example 1:

A carbon quantum dot with high fluorescence performance for oxytocin detection, its preparation method comprises the following steps:

(1) Mix quercetin, o-phenylenediamine, and deionized water evenly, and then conduct a hydrothermal reaction at 220°C for 6 hours to prepare a reaction solution; wherein, the moles of quercetin, o-phenylenediamine, and deionized water The volume ratio is 0.5mmol: 1.5mmol: 20mL;

(2) After the reaction solution prepared in step (1) is cooled, it is filtered through a membrane with a pore size of 0.22 μm, and the filtrate is transferred to a dialysis bag with a molecular weight cut-off of 2000 Da for dialysis for 24 hours and then freeze-dried to obtain a high Fluorescent properties of carbon quantum dots.

A detection method for oxytocin content, comprising the following steps:

(1) The prepared carbon quantum dots with high fluorescence performance for oxytocin detection are mixed with water to prepare a carbon quantum dot solution with a concentration of 0.5 mg/mL;

(2) Take 100 μL of the carbon quantum dot solution prepared in step (1), and add 100 μL of different concentrations of oxytocin standard solutions (0.2IU/mL, 0.36IU/mL, 0.4IU/mL, 0.6IU/mL, 0.8 IU/mL, 1.2IU/mL, 1.6IU/mL, 2IU/mL, 3IU/mL, 4IU/mL, 5IU/mL, 6IU/mL, 7IU/mL, 8IU/mL, 9IU/mL, 10IU/mL) , taking 460nm as the excitation wavelength, measure the fluorescence emission spectrum of the carbon quantum dot solution before and after adding the standard solution respectively, obtain the carbon quantum dot solution after the standard solution is added relative to the carbon quantum dot solution before the standard solution adds at the maximum emission wavelength 542nm place The change value of the fluorescence intensity;

(3) According to the change value of the fluorescent intensity obtained in step (2) and the concentration of the corresponding oxytocin standard solution, draw a standard curve to obtain a linear equation;

Wherein, the concentration of oxytocin standard solution is in the range of 0.2-5IU/mL, the linear equation is y=29298x+17654, R ² =0.9957, wherein, y is the change value of fluorescence intensity, x is the oxytocin standard solution Concentration, R is a linear fitting constant (see Figure 7, F ₀ represents the fluorescence intensity when oxytocin is not added, and F represents the fluorescence intensity when oxytocin is added);

The linear equation of the concentration of oxytocin standard solution in the range of 5-10IU/mL is y=6894x+127986, R ² =0.9928, wherein, y is the change value of fluorescence intensity, x is the concentration of oxytocin standard solution, R is a linear fitting constant (see Figure 8, F ₀ represents the fluorescence intensity when oxytocin is not added, and F represents the fluorescence intensity when oxytocin is added);

(4) Take 100 μL of the carbon quantum dot solution prepared in step (1), add 100 μL of the oxytocin solution to be detected (the known concentration is 1.67IU/mL, and measure 6 times in parallel), and use 460nm as the excitation wavelength to measure the oxytocin solution to be tested respectively. Detect the fluorescence emission spectrum of the carbon quantum dot solution before and after adding the oxytocin solution, and obtain the maximum emission wavelength of the carbon quantum dot solution after the oxytocin solution is added relative to the carbon quantum dot solution before the oxytocin solution is added. The change value of the fluorescence intensity at 542nm was substituted into the linear equation, and the concentration of the oxytocin solution to be detected was 1.69IU/mL.

Example 2:

A carbon quantum dot with high fluorescence performance for oxytocin detection, its preparation method comprises the following steps:

(1) Mix quercetin, o-phenylenediamine and deionized water evenly, and then conduct a hydrothermal reaction at 160°C for 8 hours to prepare a reaction solution; wherein, the moles of quercetin, o-phenylenediamine and deionized water The volume ratio is 0.5mmol: 0.25mmol: 10mL;

(2) After the reaction solution prepared in step (1) is cooled, it is filtered through a membrane with a pore size of 0.22 μm, and the filtrate is transferred to a dialysis bag with a molecular weight cut-off of 1000 Da for dialysis for 48 hours and freeze-dried to obtain a high Fluorescent properties of carbon quantum dots.

A detection method for oxytocin content, comprising the following steps:

(1) The prepared carbon quantum dots with high fluorescence performance for oxytocin detection are mixed with water to prepare a carbon quantum dot solution with a concentration of 0.05 mg/mL;

(2) Take 100 μL of the carbon quantum dot solution prepared in step (1), and add 50 μL of different concentrations of oxytocin standard solutions (0.2IU/mL, 0.36IU/mL, 0.4IU/mL, 0.6IU/mL, 0.8 IU/mL, 1.2IU/mL, 1.6IU/mL, 2IU/mL, 3IU/mL, 4IU/mL, 5IU/mL, 6IU/mL, 7IU/mL, 8IU/mL, 9IU/mL, 10IU/mL) , taking 460nm as the excitation wavelength, measure the fluorescence emission spectrum of the carbon quantum dot solution before and after adding the standard solution respectively, obtain the carbon quantum dot solution after the standard solution is added relative to the carbon quantum dot solution before the standard solution adds at the maximum emission wavelength 542nm place The change value of the fluorescence intensity;

(3) According to the change value of the fluorescent intensity obtained in step (2) and the concentration of the corresponding oxytocin standard solution, draw a standard curve to obtain a linear equation;

Wherein, the concentration of the oxytocin standard solution is in the range of 0.2-5IU/mL, the linear equation is y=7333x+2235, R ² =0.9908, wherein, y is the change value of the fluorescence intensity, x is the oxytocin standard solution Concentration, R is a linear fitting constant;

The concentration of the oxytocin standard solution is in the range of 5-10IU/mL, the linear equation is y=1518x+31106, R ² =0.9878, wherein, y is the change value of the fluorescence intensity, x is the concentration of the oxytocin standard solution, R is a linear fitting constant;

(4) Take 100 μL of the carbon quantum dot solution prepared in step (1), add 50 μL of the oxytocin solution to be detected (the known concentration is 3.75IU/mL, and measure 6 times in parallel), and use 460nm as the excitation wavelength to measure the oxytocin solution to be tested respectively. Detect the fluorescence emission spectrum of the carbon quantum dot solution before and after adding the oxytocin solution, and obtain the maximum emission wavelength of the carbon quantum dot solution after the oxytocin solution is added relative to the carbon quantum dot solution before the oxytocin solution is added. The change value of the fluorescence intensity at 542nm was substituted into the linear equation, and the concentration of the oxytocin solution to be detected was 3.7IU/mL.

Example 3:

A carbon quantum dot with high fluorescence performance for oxytocin detection, its preparation method comprises the following steps:

(1) Mix quercetin, o-phenylenediamine and deionized water evenly, and then conduct a hydrothermal reaction at 240°C for 4 hours to prepare a reaction solution; wherein, the moles of quercetin, o-phenylenediamine and deionized water The volume ratio is 0.5mmol: 2mmol: 25mL;

(2) After the reaction solution prepared in step (1) is cooled, it is filtered through a membrane with a pore size of 0.22 μm, and the filtrate is transferred to a dialysis bag with a molecular weight cut-off of 5000 Da for dialysis for 12 hours and freeze-dried to obtain a high Fluorescent properties of carbon quantum dots.

A detection method for oxytocin content, comprising the following steps:

(1) The prepared carbon quantum dots with high fluorescence performance for oxytocin detection are mixed with water to prepare a carbon quantum dot solution with a concentration of 1.5 mg/mL;

(2) Take 50 μL of the carbon quantum dot solution prepared in step (1), and add 100 μL of different concentrations of oxytocin standard solutions (0.2IU/mL, 0.36IU/mL, 0.4IU/mL, 0.6IU/mL, 0.8 IU/mL, 1.2IU/mL, 1.6IU/mL, 2IU/mL, 3IU/mL, 4IU/mL, 5IU/mL, 6IU/mL, 7IU/mL, 8IU/mL, 9IU/mL, 10IU/mL) , taking 460nm as the excitation wavelength, measure the fluorescence emission spectrum of the carbon quantum dot solution before and after adding the standard solution respectively, obtain the carbon quantum dot solution after the standard solution is added relative to the carbon quantum dot solution before the standard solution adds at the maximum emission wavelength 542nm place The change value of the fluorescence intensity;

(3) According to the change value of the fluorescent intensity obtained in step (2) and the concentration of the corresponding oxytocin standard solution, draw a standard curve to obtain a linear equation;

Wherein, the concentration of the oxytocin standard solution is within the range of 0.2-5IU/mL, the linear equation is y=21382x+12486, R ² =0.9943, wherein, y is the change value of the fluorescence intensity, and x is the oxytocin standard solution Concentration, R is a linear fitting constant;

The linear equation of the concentration of oxytocin standard solution in the range of 5-10IU/mL is y=5625x+91977, R ² =0.9937, wherein, y is the change value of fluorescence intensity, x is the concentration of oxytocin standard solution, R is the linear fitting constant;

(4) Take 50 μL of the carbon quantum dot solution prepared in step (1), add 100 μL of the oxytocin solution to be detected (the known concentration is 6.67IU/mL, measured in parallel 6 times), and use 460nm as the excitation wavelength to measure the oxytocin solution to be detected respectively. Detect the fluorescence emission spectrum of the carbon quantum dot solution before and after adding the oxytocin solution, and obtain the maximum emission wavelength of the carbon quantum dot solution after the oxytocin solution is added relative to the carbon quantum dot solution before the oxytocin solution is added. The change value of the fluorescence intensity at 542nm was substituted into the linear equation, and the concentration of the oxytocin solution to be detected was 6.91IU/mL.

Test case

The characterization and performance of the carbon quantum dots with high fluorescence performance for the detection of oxytocin prepared in Examples 1-3 are basically the same. Taking Example 1 as an example, the following detection is carried out.

1. The carbon quantum dots with high fluorescence performance for oxytocin detection prepared in Example 1 were subjected to high-resolution transmission electron microscopy, particle size, infrared and ultraviolet detection, and the results are shown in Figures 1-4.

It can be seen from Figure 1-2 that the synthesized carbon dots have a uniform particle size, with an average particle size of 8.28nm.

It can be seen from Figure 3 that 3360cm ^-1 and 3031cm ^-1 are the stretching vibration peaks of amino and hydroxyl groups, 1621-1460cm ^-1 is the stretching vibration peak of the benzene ring skeleton C=C, and 1276cm ^-1 is the stretching vibration peak of CN substitution on the benzene ring. 745.64cm ^-1 is the CH stretching vibration peak on the ortho-disubstituted benzene ring, indicating that the synthesized carbon dots have a benzene ring skeleton, and the surface has hydroxyl and amino groups. The existence of a large number of polar hydroxyl groups and amino groups makes the carbon dots have good water solubility.

It can be seen from Figure 4 that the carbon dot solution has maximum absorption at 280nm and 230nm, further indicating that the carbon dots have a conjugated double bond structure.

2. The carbon quantum dot solution with high fluorescence performance for oxytocin detection prepared in Example 1 was subjected to fluorescence spectrum detection, and the results are shown in FIG. 5 . It can be seen from FIG. 5 that the maximum excitation wavelength of the present carbon quantum dot is 460nm, and the maximum emission wavelength is 542nm.

3. The carbon quantum dot solution with high fluorescence performance for oxytocin detection prepared in Example 1 was continuously irradiated for 10 h with an excitation light of 460 nm, and its fluorescence signal is shown in FIG. 6 . It can be seen from Fig. 6 that the carbon dots prepared by the present invention have strong photobleaching resistance and better photostability.

4. The influence of interfering substances on the determination results of oxytocin

The carbon quantum dots with high fluorescence performance for oxytocin detection prepared in Example 1 were configured into 50 μL carbon quantum dot solution (1 mg/mL), and 100 μL of oxytocin standard solution (mass concentration of 1.67 μL) was added with a concentration of 1 IU/mL ug/mL), and then add 50 μL of water or aqueous solutions of different interfering substances (6 times in parallel for each group), and use 460nm as the excitation wavelength to measure the fluorescence of the reaction system at the maximum emission wavelength of 542nm after adding water and adding different interfering substances. Intensity; the fluorescence intensity of the reaction system after adding the interfering substance is compared with the fluorescence intensity of the reaction system with water, and the relative error (%) is obtained. The results are shown in Table 1.

As can be seen from Table 1, common interfering ions such as common metal ions in water, various amino acids that may be introduced in the extraction process of oxytocin and the adjuvant chlorobutanol in oxytocin injection have no effect on its determination results ( The relative error is within ±5%, and the influence of interfering substances on the determination can be ignored), indicating that the carbon quantum dots have good selectivity to oxytocin, and are not interfered by other substances during determination, and can be used for oxytocin determination.

Table 1 The influence of interfering substances on the measurement results (n=6)

5. Accuracy and precision

The measurement results of Examples 1-3 were carried out for recovery and precision measurement, and the results are shown in Table 2. It can be seen from Table 2 that the carbon quantum dots of the present invention have good accuracy and precision for detecting the content of oxytocin.

Table 2 Measurement results of method accuracy and precision (n=6)

6. Detection limit

The fluorescence intensity of the carbon quantum dot solution before the standard solution is added in the embodiment 1 step (2) is repeatedly measured 11 times, calculates the standard deviation of the blank fluorescence intensity, obtains the slope of the standard curve according to the step (3) standard curve, and uses the signal-to-noise ratio S /N=3, calculate the detection limit LOD with the following formula:

LOD=3×Standard deviation of blank fluorescence intensity/Slope of standard curve

Available, the detection limit of oxytocin is 0.0196IU/mL.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within range.

Claims (6)

1. An application of oxytocin detection of high fluorescence performance carbon quantum dots in the detection of oxytocin content, characterized in that, the preparation method for oxytocin detection of high fluorescence performance carbon quantum dots comprises the following steps : (1) Mix carbon source, nitrogen source and deionized water evenly, and then carry out hydrothermal reaction to prepare a reaction solution; (2) After cooling the reaction solution prepared in step (1), it is filtered, dialyzed, and freeze-dried in sequence to obtain carbon quantum dots with high fluorescence performance for oxytocin detection; In step (1), the carbon source is quercetin; In step (1), the nitrogen source is o-phenylenediamine. 2. The application of carbon quantum dots for oxytocin detection with high fluorescence performance in the detection of oxytocin content according to claim 1, characterized in that, in step (1), carbon source, nitrogen source and deionized water The molar volume ratio is 0.5mmol: 0.25-2mmol: 10-25mL. 3. The application of carbon quantum dots with high fluorescence performance for detecting oxytocin according to claim 1, characterized in that, in step (1), the hydrothermal reaction is carried out at 160-240°C 4-8h. 4. a detection method of oxytocin content, is characterized in that, comprises the following steps: (1) Mixing the carbon quantum dots with high fluorescence performance for detecting oxytocin described in any one of claims 1-3 and water to prepare a carbon quantum dot solution; (2) In the carbon quantum dot solution prepared in step (1), add different concentrations of oxytocin standard solutions, and use 460nm as the excitation wavelength to measure the fluorescence emission of the carbon quantum dot solution before and after adding the standard solution Spectrum, after the standard solution is added, the carbon quantum dot solution is obtained relative to the fluorescence intensity change value of the carbon quantum dot solution at the maximum emission wavelength before the standard solution is added; (3) According to the change value of fluorescence intensity obtained in step (2) and the concentration of the corresponding oxytocin standard solution, draw a standard curve to obtain a linear equation; (4) In the carbon quantum dot solution prepared in step (1), add the oxytocin solution to be detected, and use 460nm as the excitation wavelength to measure the fluorescence of the carbon quantum dot solution before and after adding the oxytocin solution to be detected Emission spectrum, obtain the change value of the fluorescence intensity of the carbon quantum dot solution at the maximum emission wavelength of the carbon quantum dot solution after the oxytocin solution to be detected is added relative to the carbon quantum dot solution before the oxytocin solution to be detected is added, and substitute into the linear equation to obtain the oxytocin solution to be detected concentration of the solution. 5. The method for detecting the content of oxytocin according to claim 4, characterized in that, in step (1), the concentration of the carbon quantum dot solution is 0.05-1.5 mg/mL. 6. The detection method of oxytocin content according to claim 4, characterized in that, in step (2), the volume ratio of the carbon quantum dot solution to the oxytocin standard solution is 1:0.5-2.